audiothekar: disable parallel building

pkgs/by-name/au/audiothekar/package.nix

@@ -20,6 +20,11 @@ buildDotnetModule rec {
 
   projectFile = "Audiothekar.sln";
 
+  # > Unable to use package assets cache due to I/O error. This can occur when
+  # > the same project is built more than once in parallel. Performance may be
+  # > degraded, but the build result will not be impacted.
+  enableParallelBuilding = false;
+
   doCheck = false;
 
   nugetDeps = ./deps.json;